1. Field of the Invention
This invention relates to a new surfactant base for soapless lubricants known per se containing alkylamines and/or amphoteric compounds, optionally water and other auxiliaries and additives.
The invention also relates to the use of the lubricants as chain lubricants in the food industry. More particularly, the lubricants according to the invention are used for lubricating, cleaning and disinfecting automatic chain and belt conveyors which are used in the packaging of foods, preferably beverages, in glass and plastic bottles, cans, glasses, barrels, kegs, paper and cardboard containers and the like.
2. Statement of Related Art
The chain lubricants hitherto used for lubrication are based on the one hand on fatty acids in the form of their water-soluble alkali metal or alkanolamine salts or on fatty amines in the form of their organic or inorganic salts.
DE-A-23 13 330 describes soap-based lubricants containing aqueous mixtures of C.sub.16-18 fatty acid salts and surfactants.
Apart from these soap-based lubricants, lubricants based on primary fatty amines are otherwise mainly used. Thus, DE-A-36 31 953 describes a process for lubricating chain-type bottle conveyors in bottling plants, more particularly in breweries, and for cleaning the conveyors with a liquid cleaner which is characterized in that the chain-type bottle conveyors are lubricated with conveyor lubricants based on neutralized primary fatty amines which preferably contain 12 to 18 carbon atoms and an unsaturated component of more than 10% and in that the bottle conveyors are cleaned with cationic cleaning preparations based on the quaternary ammonium compounds, such as alkyl trimethyl ammonium chloride, dialkyl dimethyl ammonium chloride and alkyl dimethyl benzyl ammonium chloride, or organic acids.
Finally, chain lubricants without any of the disadvantages mentioned above are known from the prior art. Thus, EP-A-0 044 458 describes lubricant preparations which are substantially free from fatty acid soaps and which in addition contain carboxylated nonionic surfactants and an acyl sarcosinate. The pH value of these products is in the range from 7 to 11 and, accordingly, is preferably in the neutral to alkaline range.
Finally, DE-A-38 31 448 relates to water-containing, soapless lubricant preparations which form clear solutions in water, to a process for their production and to their use in particular as lubricants for the transport of glass bottles or polyethylene terephthalate bottles. The substantially neutral water-containing lubricant preparations (pH 6 to 8) contain alkyl benzenesulfonates, alkoxylated alkanol phosphates and alkanecarboxylic acids, optionally in addition to typical solubilizers, solvents, foam inhibitors and disinfectants.
Unfortunately, the two products described above are attended by the following three disadvantages:
1. They are microbiologically unfavorable because they create excellent growth conditions for microorganisms. PA1 2. In addition, they show minimal cleaning power. PA1 R.sup.1 represents hydrogen, an alkyl group containing 1 to 4 carbon atoms, a hydroxyalkyl group containing 1 to 4 carbon atoms or a group --R.sup.3 COOM, PA1 R.sup.2 --only for the case where M is a negative charge--represents hydrogen, an alkyl group containing 1 to 4 carbon atoms or a hydroxyalkyl group containing 1 to 4 carbon atoms, PA1 R.sup.3 is a saturated or mono- or polyunsaturated, linear or branched alkyl group containing 1 to 12 carbon atoms which may optionally be substituted by --OH, --NH.sub.2, --NH--, --CO--, --(CH.sub.2 CH.sub.2 O).sub.1 -- or --(CH.sub.2 CH.sub.2 CH.sub.2 O).sub.1 --, PA1 R.sup.4 is a substituted or unsubstituted, linear or branched, saturated or mono- or polyunsaturated alkyl group containing 6 to 22 carbon atoms which may contain at least one amine, imine, hydroxy, halogen and/or carboxy group as substituent, a substituted or unsubstituted phenyl group which may contain at least one amine, imine, hydroxy, halogen, carboxy group and/or a linear or branched saturated or mono- or polyunsaturated alkyl group containing 6 to 22 carbon atoms as substituent(s), PA1 R.sup.5 is hydrogen or--independently of R.sup.4 --has the same meaning as R.sup.4, PA1 X.sup.- is an anion from the group consisting of amidosulfonate, nitrate, halide, sulfate, hydrogen carbonate, carbonate, phosphate or R.sup.6 --COO.sup.-, where PA1 R.sup.6 is hydrogen, a substituted or unsubstituted, linear or branched alkyl group containing 1 to 20 carbon atoms or alkenyl group containing 2 to 20 carbon atoms, which may contain a hydroxy, amine or imine group as substituent, or a substituted or unsubstituted phenyl group which may contain an alkyl group with 1 to 20 carbon atoms as substituent, and PA1 R.sup.7 and R.sup.8 independently of one another represent a substituted or unsubstituted, linear or branched alkyl group containing 1 to 20 carbon atoms or alkenyl group containing 2 to 20 carbon atoms, which may contain at least one hydroxy, amine or imine group as substituent, or a substituted or unsubstituted phenyl group which may contain an alkyl group with 1 to 20 carbon atoms as substituent, PA1 M is hydrogen, alkali metal, ammonium, an alkyl group containing 1 to 4 carbon atoms, a benzyl group or a negative charge, PA1 n is an integer of 1 to 12, PA1 m is an integer of 0 to 5 and PA1 l is a number of 0 to 5, PA1 R is a saturated or mono- or polyunsaturated linear alkyl group containing 10 to 18 carbon atoms, which may optionally be substituted by --CO--, more particularly an unsubstituted, saturated linear alkyl group containing 12 to 14 carbon atoms, PA1 R.sup.1 is hydrogen, an alkyl group containing 1 to 3 carbon atoms or a group --CH.sub.2 CH.sub.2 OH, more particularly hydrogen or an alkyl group containing 1 to 3 carbon atoms, PA1 R.sup.2 is hydrogen or an alkyl group containing 1 to 3 carbon atoms, PA1 R.sup.3 is a methylene or dimethylene group, more particularly a methylene group, PA1 M is hydrogen or a negative charge, PA1 n=2 or 3, more particularly 2, PA1 m=0, 1 or 2, more particularly 0. PA1 R.sup.4 represents: PA1 and X.sup.- is an anion from the group consisting of amidosulfonate, nitrate, halide, sulfate, hydrogen carbonate, carbonate, phosphate or R.sup.6 --COO.sup.-, where R.sup.6 is hydrogen, a saturated, mono- or polyunsaturated, linear or branched, optionally --OH--, --NH.sub.2 -- or --NH-substituted alkyl group with 1 to 20 carbon atoms or a corresponding alkenyl group with 2 to 20 carbon atoms or a substituted or unsubstituted phenyl group which may contain an alkyl group with 1 to 20 carbon atoms as substituent and PA1 R.sup.5 has the same meaning as R.sup.4 or is hydrogen. PA1 a substituted or unsubstituted, linear or branched alkyl group containing 1 to 20 carbon atoms or alkenyl group containing 2 to 20 carbon atoms which may contain at least one hydroxy, amine or imine group as substituent, or PA1 a substituted or unsubstituted phenyl group which may contain an alkyl group with 1 to 20 carbon atoms as substituent. PA1 R.sup.1 is an alkyl group containing 4 to 22 carbon atoms, PA1 (G) is a sugar unit containing 5 or 6 carbon atoms and PA1 p is a number of 1 to 10.
3. Finally, their foaming behavior is difficult to control.
DE-A-39 05 548 describes lubricants containing at least one secondary and/or tertiary amine and/or salts of such amines.
Nowadays, beverages are often bottled in polyethylene terephthalate (PET) bottles. Returnable PET bottles have been successfully used in particular for beverages containing carbon dioxide, such as mineral waters and lemonade. During their transport in bottling plants, these bottles come into contact with chain conveyor lubricants. A more or less large part of the chain conveyor lubricant remains on the bottles, dries and results in partial damage to the bottles. More particularly, cracks, so-called stress cracks, have been found in the PET material. In extreme cases, this results in bursting of the bottles.
For this reason, soapless chain conveyor lubricants have hitherto been used almost exclusively for lubricating bottles, being tested by manufacturers for their particular suitability and then passed. Alkylamine-based chain conveyor lubricants generally known in the prior art which, as mentioned above, are widely used for the transport of other beverage containers apparently cause damage to the bottles.